Signal lamp



FIG. 1 is a top perspective view of a signal lamp showing my new design;

FIG. 2 is a front side elevation view thereof;

FIG. 3 is a rear side elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The parts shown in broken lines are included for the purpose of illustrating portions of the “article” and form no part of the claimed design. 

The ornamental design for a a signal lamp, as shown and described. 